iStock/Thinkstock(WASHINGTON) — Top congressional leaders met with senior intelligence and law enforcement officials Thursday in a series of White House-brokered meetings to review highly-classified information about the Russia investigation, including possible details about a reported FBI informant in touch with several Trump campaign advisers during the 2016 presidential campaign.

And in a surprise development, the president’s new lawyer handling the Russia investigation, Emmet Flood, attended and participated in at least part of the briefings as did White House chief of staff John Kelly, sources confirmed to ABC News.

Democrats have raised questions about the appropriateness of any White House involvement, concerned that it would further politicize what is supposed to be an independent probe.

President Donald Trump has said the briefings could provide proof of his unsubstantiated claim the FBI was likely spying on his campaign.

Responding to questions about why Flood and Kelly were there, White House press secretary Sarah Sanders issued a statement saying “Neither Chief Kelly nor Mr. Flood actually attended the meetings but did make brief remarks before the meetings started to relay the President’s desire for as much openness as possible under the law.”

“They also conveyed the President’s understanding of the need to protect human intelligence services and the importance of communication between the branches of government. After making their brief comments they departed before the meetings officially started,” her statement continued.

At noon, House Intelligence Committee Chairman Devin Nunes, a California Republican, and House Oversight Committee Chairman Trey Gowdy, a South Carolina Republican, met at the Justice Department with FBI Director Chris Wray, Director of National Intelligence Dan Coats and Ed O’Callaghan, a Justice Department official and deputy to Deputy Attorney General Rod Rosenstein.

Nunes and Gowdy left about an hour later without speaking to reporters.

Rep. Adam Schiff, D-Calif., the top Democrat on the House Intelligence Committee, joined Gowdy and Nunes in the initial briefing at noon, at House Minority Leader Nancy Pelosi’s request after Democrats were initially excluded by the White House.

House Speaker Paul Ryan, R-Wis., attended the noon briefing as well because he was scheduled to travel to Texas for a fundraiser for House Republicans, according to an aide. Other congressional leaders were scheduled to get their DOJ briefing Thursday afternoon on Capitol Hill.

Ryan later put out a statement referring to the House Intelligence Committee Nunes chairs, saying “Inherent in the committee’s work is the responsibility to ask tough questions of the executive branch. That is why we have insisted and will continue to insist on Congress’s constitutional right to information necessary for the conduct of oversight.”

Kelly had helped arrange what was originally planned as just a DOJ briefing for Nunes and Godwy as Republicans continue to spar with the Justice Department on requests for documents and information related to a myriad of GOP investigations into the department.

The meeting comes as President Trump continues to stoke unsubstantiated claims that the FBI planted a spy inside his presidential campaign.

“A lot of bad things have happened. We now call it ‘Spygate,’” Trump said as he departed the White House Wednesday. Countering Trump, Schiff has said the controversy should be called “Lie-gate.”

“Nothing we heard today has changed our view that there is no evidence to support any allegation that the FBI or any intelligence agency placed a spy in the Trump campaign, or otherwise failed to follow appropriate procedures and protocols,” Schiff said.

Following protests from top Democrats and Republicans, the White House arranged a second briefing for members of the Gang of Eight, the bipartisan group of top lawmakers in both chambers who have access to the most sensitive intelligence.

As of Thursday morning, some details remained in flux.

The meetings are the result of a subpoena Nunes issued earlier this month demanding classified documents related to the source, a request the Justice Department denied over national security concerns. The Washington Post and New York Times first reported that the FBI sent an informant to talk to several campaign aides during the 2016 election as evidence that a second special counsel is needed.

After Nunes threatened to move to hold Attorney General Jeff Sessions in contempt of Congress over the refusal, the Justice Department invited Nunes and House Oversight Committee Chairman Trey Gowdy to DOJ for a briefing on the documents.

On Sunday, Trump entered the fray , calling for the DOJ to investigate whether the FBI “infiltrated or surveilled” his presidential campaign, and whether it was ordered by Obama administration officials – allegations he has not backed up with evidence.

The Justice Department subsequently directed the DOJ inspector general, the agency’s watchdog, to expand its ongoing investigation of surveillance of Trump campaign adviser Carter Page during the presidential election to include the president’s concerns.

Nunes has said the request relates to classified information relevant to his ongoing investigation into allegations of political bias at the Justice Department related to the Russia investigation, but it was unclear to both Republicans and Democrats Thursday what information the group will learn about the alleged informant.

House Minority Leader Nancy Pelosi, D-Calif., called the meeting “unacceptable and very inappropriate” and accused Republicans of setting up the session to learn information to aid Trump’s defense in the Russia investigation.

Senate Minority Leader Chuck Schumer, D-N.Y., said Thursday that the meeting “should be called off,” and called Nunes a “known partisan whose only intent is to undermine the Mueller investigation.”

Pelosi and Schiff have also expressed concern that Kelly, the White House chief of staff, could potentially participate in a meeting related to the ongoing Trump-Russia investigation. The Justice Department said Kelly would participate in both meetings, but Schiff said he had been informed by the head of one intelligence agency that Kelly would not take part in the sessions.